DW handle's pre-made adventure material as well, for example The Bloodstone Idol is more or less a traditional adventure. On the other end of the spectrum, I think the game totally handles zero-prep games. The GM asks lots of questions and builds things on the fly based on the cool stuff in his head and the players' answers.
It can be challenging to run a game 'without a net' though. Check out one of the Dungeon Starters that I put together, for example The Goblin Hole
. They're designed to give you a bunch of thematically related material to work with so that you can just sit down and play at a moment's notice (but they don't get in the way of players' answers, they don't prewrite the story, and don't get in the way of the front mechanic that kicks in after your first session).